Channel-consistency following unilateral stroke: an examination of patient communications across verbal and nonverbal domains.

One way in which the dyadic communicative process can go awry is for one or both parties to send channel-inconsistent communications - communications in which the verbal and nonverbal elements are not matched in emotional valence (e.g., uttering positive words with a frown). We hypothesized that unilateral stroke patients would be likely to send such messages. Given the verbal impairments typically associated with left hemisphere damage (LHD), e.g., agrammatism, and the nonverbal impairments typically associated with right hemisphere damage (RHD), we expected LHD and RHD patients to send messages in which the impaired channel was perceived as inconsistent with the unimpaired channel. Ten LHD, 11 RHD and six normal control patients were videotaped while engaging in social interaction. Observers made judgments about the valence of the patients' (1) words (based on transcripts of the interactions), and (2) facial expressions (based on soundless videos of the interactions). Analysis of word-face difference scores revealed a significant linear trend, with messages of LHD patients judged more positive in facial expression than in verbal content, messages of RHD patients judged more positive in verbal content than in facial expression, and messages of control patients judged channel-consistent (similar in valence across facial and verbal channels).